Exercising in the Haze: A Real-Life Guide for Women and Mums in Singapore

You can keep moving through the haze. You just need to move smarter: shorter, easier and mostly indoors on the bad days.

This morning my air quality app showed a big red 193 and the word “Unhealthy”. The kids asked why the sky looked “dusty”, my run was cancelled before I’d even laced up, and my inbox filled with the same question from clients: should I still train?

The haze has been on and off since early September. NEA’s 24-hour PSI went into the unhealthy range on 4 September, the first time since October 2023, and hit this year’s high of 164 in central Singapore on 29 September. The Met Service expects the dry season to drag on until late October or early November, so this isn’t a one-week thing.

This post covers how to read the numbers, and what to do if you’re a regular exerciser, pregnant, a runner, or trying to keep kids moving at home.

First: check the right number

The number on your app might not be the number NEA’s advice is based on. That red 193 on my phone was a US AQI reading, not Singapore’s PSI.

24-hour PSI (NEA, haze.gov.sg, myENV app): an average over the past 24 hours. All of NEA’s health advice is based on this. Use the forecast to plan tomorrow.
1-hour PM2.5 (also on NEA): what the air is like right now. Use it to decide about the next hour, like whether to do that walk now or later.
AQI apps (aqicn, IQAir and similar): use the US scale on very recent PM2.5. They usually read higher than PSI and react faster. Useful for spotting a bad hour, but don’t compare their number directly with NEA’s bands.

NEA’s advice by PSI band:

24-hr PSI	Healthy adults	Pregnant, children, elderly
0–100 (Good/Moderate)	Normal activities	Normal activities
101–200 (Unhealthy)	Reduce prolonged or strenuous outdoor exertion	Minimise prolonged or strenuous outdoor exertion
201–300 (Very unhealthy)	Avoid prolonged or strenuous outdoor exertion	Minimise outdoor activity
300+ (Hazardous)	Minimise outdoor activity	Avoid outdoor activity

“Prolonged” means several hours of continuous exposure. “Strenuous” means a lot of effort. If you have asthma or another lung or heart condition, NEA’s advice is stricter: avoid prolonged or strenuous outdoor exertion once PSI goes above 100.

If you exercise regularly

Keep training, but take it indoors and turn the intensity down a notch. Your fitness habit is worth protecting.

A large 2025 review in BMC Medicine pooled data on over 1.5 million adults. Regular exercise cut the risk of dying during the study period by about 30%. In places where yearly PM2.5 averaged 25 µg/m³ or more, that benefit roughly halved, to 12–15%. The researchers’ own advice: don’t stop, but check air quality, choose cleaner routes and ease off on polluted days.

What that looks like in practice:

Move it indoors. Strength training in an air-conditioned gym or studio is the easiest swap. Windows closed, air con on, a purifier if there is one.
Lift instead of run. Strength sessions are short bursts with rest in between. You breathe far less air than in 45 minutes of continuous cardio.
Shorten the outdoor bits. A 20-minute easy walk is very different from a two-hour hike.
Lower the effort. If you’d normally push to 8/10, cap it at 6/10. You can talk in full sentences? Good.
Skip the outdoor workout entirely when the 1-hour PM2.5 band is high or you can smell smoke.

One honest note: you’ll see scary posts saying haze “cancels” your exercise or gives you cancer. Those studies are real, but they mostly look at years of exposure in heavily polluted cities. A few weeks of sensible choices during the haze is a very different picture. Don’t panic. Adjust.

If you’re pregnant

Keep moving, but move it all indoors while the PSI is unhealthy. NEA puts pregnant women in the vulnerable group, so the advice is to minimise prolonged or strenuous outdoor exertion, not just reduce it.

Why the extra caution? You’re already breathing more air per minute in pregnancy, and research on wildfire smoke, which is close to what we get here, links higher exposure to a higher risk of preterm birth. A large 2025 US study in a Lancet journal found the strongest links in the second trimester and with intense smoke late in pregnancy. The individual risk is small, but it’s an easy one to reduce.

Do:

Swap outdoor walks for indoor ones: a mall loop, a treadmill, or your condo gym.
Keep your strength sessions going indoors. They help with energy, sleep and back pain, and none of that has changed.
Run a HEPA purifier in the bedroom and keep windows closed.
Stay extra hydrated. Haze days are often hot and still.

Don’t:

Rely on an N95 to make outdoor exercise OK. MOH has advised that N95 masks aren’t suitable for pregnant women, as they make breathing harder. Use one for getting from A to B if you need to, not for a workout.
Push through breathlessness, dizziness or chest tightness. Stop, sit, and call your doctor if it doesn’t settle.

If you have asthma, or your gynae has given you specific advice, follow that first.

If cardio is your thing (runners, cyclists, Hyrox crew)

This is the group that needs to adjust most. Long, hard outdoor cardio is exactly the “prolonged and strenuous” exertion NEA tells everyone to cut back.

When you run hard you breathe much faster and deeper, often through your mouth, so far more fine particles reach your lungs. “Sweating it out” doesn’t help: sweat doesn’t remove anything you’ve breathed in.

I’m training for a Hyrox race next month, so I get the frustration. Here’s how I’m handling it:

Treadmill or indoor rower for the long, easy sessions. Boring, yes. Effective, also yes.
Turn intervals into indoor circuits. Sled-style pushes, wall balls, rower or bike sprints, burpees. Hard work, indoors, short bursts.
Run outside only on the clearer days, and early. Check the 1-hour PM2.5 before you go, not just yesterday’s PSI.
Don’t chase paces. If you do run outside, run by feel and keep it easy.
Race coming up? Check the organiser’s haze policy. Events can be modified or cancelled once the PSI forecast goes above 100.

A few weeks of indoor training won’t undo months of fitness. Pushing through a cough or tight chest to hit a session might set you back more.

If you’re keeping kids moving

Children are in the vulnerable group too, so outdoor play gets cut back. The kids still have energy to burn, though, and that’s usually the real challenge.

Why kids need extra care: they breathe faster than adults for their size, they play hard without pacing themselves, and they won’t tell you their chest feels tight until they’re coughing.

Indoor ideas that actually work in a Singapore flat:

Animal walks race: bear crawls, crab walks, frog jumps, down the corridor and back.
Living-room circuit: 30 seconds each of squats, star jumps, wall sits, and “floor is lava” on cushions. Let them pick the music.
Train together: do your strength session while they copy you with a water bottle or soft toy as a weight. They love being the coach, too.
Dance party or a kids’ yoga video for the wind-down.
Indoor venues: indoor playgrounds, trampoline parks, climbing gyms and indoor pools in malls or with good ventilation.

A few practical bits:

Check your school’s haze plan. Schools follow MOE guidance and will move PE and recess indoors as needed.
Masks: regular N95s aren’t designed for children’s faces, and MOH has advised they aren’t suitable for young kids. Kids’ KF94s help on the school run, but only if they fit snugly, and most kids pull them down within minutes. Treat a mask as a backup for getting around, not a reason to play outside.
Close windows and run a purifier in the room where they sleep.

What I’m doing at home

I’ll be honest: I love being outdoors, and I miss it. But my kids are sensitive to the haze and have been coughing on and off since it started, so this is what’s changed in our house:

I haven’t run outside once since the haze started. Running in smoke while writing about lung health felt like a contradiction. So it’s the “boring” treadmill for now, and my training hasn’t suffered for it.
I’ve stopped cycling on the bad days. I normally cycle around town and kept going on the lightly hazy days. On days like today it’s the bus, or a Grab if the budget allows.
We check the numbers before saying yes. Last week football went ahead because the air was fairly OK. Today it’s cancelled.
Indoor playgrounds instead of parks. Not my favourite, but the kids still get to run wild.
An air purifier in every room. Home is where we spend most of our hours, so that’s where clean air matters most.
Masks for getting around. The kids have KF94s for the school run, though keeping them on properly is a daily battle.

None of it is perfect. It’s just a set of small swaps that keep us moving until the rain comes back.

Your haze-week game plan

Check NEA the night before. Plan tomorrow with the 24-hour PSI forecast.
Check the 1-hour PM2.5 before you head out. Haze changes hour to hour with the wind.
Default to indoors while the PSI is above 100: studio, gym, condo gym, living room.
Swap long cardio for strength or short indoor intervals.
Lower the dial. Same habit, less intensity, shorter outdoor time.
Clean up your home air. Windows closed, air con on, HEPA purifier in the bedroom.
Use masks for getting around, not for workouts. Kids’ masks only help if they fit snugly, and skip adult N95s for pregnant women and young kids.
Drink more water. Haze weeks have been hot and dry.
Be kind to yourself. A lighter week is still a week where you showed up.

When to stop and get checked

Stop exercising and rest if you feel unusually breathless, wheezy, dizzy, or get chest tightness, a headache or a cough that won’t settle. See a doctor if it doesn’t ease with rest, if you have asthma and your reliever isn’t helping, or if you’re pregnant and anything feels off. For chest pain or severe breathlessness, call 995.

Train indoors with us

All our studio sessions happen indoors at Core Collective Dempsey, i12 Katong and Tanjong Pagar, so the haze doesn’t have to stop your progress. Prefer to stay home? Our coaches can come to you, or train you online, including pregnancy-safe sessions and workouts with your kids alongside.

Get started with ActiveWomen or WhatsApp us on +65 8866 4050.

Progress is never linear. Haze weeks included.

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